This study examines the field of library social work through a mixed-methods design, exploring the characteristics, practices, and experiences of library social workers to investigate the barriers and facilitators to developing, implementing, and practicing library social work in the United States from their own perspectives. The results emphasize variation in library social workers’ education, licensure, professional credentials, and the geographic and organizational contexts in which they practice. Additionally, social workers in public libraries not only serve a wide variety of patron populations but also provide assistance to library staff and the larger community.